Today's networked computing environments are used in businesses for generating and storing large amounts of critical data. The systems used for moving, storing, and manipulating this critical data are expected to very highly reliable. “High Availability” systems employ various means for optimizing reliability.
High Availability systems are generally designed such that single points of failure are avoided in the portions of the system considered “critical”. For example, multiple central processing units may provide redundancy, and multiple power supplies ensure protection against the failure of one. However, there are other parts of the system that can become single points of failure, but do not currently employ high availability mechanisms.
One area in which it would be advantageous to provide high availability is in the manufacturing test circuits used in the systems. Manufacturing test circuits are used for monitoring and testing such things as voltage margins, clock margins, fan speeds, temperature controls, and the like for the components and modules in the system. Another area in which it would be advantageous to provide high availability is in the identification circuitry used for uniquely identifying modules in the systems. If a fault occurs in the manufacturing test circuitry or in the identification circuitry, a system level fault may result. What is needed is manufacturing test and module identification circuitry that employs mechanisms for avoiding single points of failure.